Karem Aircraft has unveiled a new AR40 compound helicopter design it is offering for the U.S. Army’s Future Attack Reconnaissance Aircraft-Competitive Prototype (FARA-CP) program, at the AUSA 2019 Exposition.
The AR40 is an active-rotor, winged, compound helicopter design with a three-blade rigid main rotor and a swiveling tail rotor.
The main rotor, with a diameter of 11 m, uses Karem’s Optimum Speed Rotor technology, where the speed of the rotor is adjusted between the vertical and horizontal phases of flight to maintain the optimum loading on the blades to maximize propulsive efficiency. The system also lets each of the three blades on the rotorcraft’s main rotor to be controlled individually, instead of forcing the blades to move in unison as is the case with a traditional swashplate system.
The tail rotor will be angled backwards in horizontal flight acting as a pusher propeller and, according to the company, the aircraft’s vertical stabilizer will compensate for torque from the main rotor. The aircraft also has a tilting wing with a wingspan of 12.2m. The wing can provide the majority of the aircraft’s lift while in horizontal flight. It will be tilted vertically during the ascent and descent for aerodynamic reasons.
The aircraft will be powered by a single GE Aviation T901 engine which was selected by the Army for its Improved Turbine Engine Program (ITEP). Karem claims that the AR40 will have a maximum speed of around 220kt.
The aircraft’s cockpit has side-by-side seating configuration. There is also a small cabin behind the cockpit that can accommodate four passengers, such as special operations forces.
Karem is partnering with Northrop Grumman and Raytheon on the AR40. Karem is contributing its rotor and drive technologies and is leading the design and prototyping process. Northrop is providing production and product support, as well as avionics expertise. Raytheon is the mission systems integrator and modular open systems architect.